package com.example.jpetstoreback.controller;

import com.example.jpetstoreback.common.CommonResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.UUID;

@Slf4j
@Controller
@RequestMapping("/catalog/")
public class CatalogController {

    @Value("${upload.path}")
    private String basePath;

    /**
     * 文件上传
     * @param file
     * @return
     */
    @PostMapping("upload")
    @ResponseBody
    public CommonResponse<String> upload(MultipartFile file){
        //file是临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除

        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));

        //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String filename = UUID.randomUUID().toString() + suffix;

        //创建目录对象
        File dir = new File(basePath);
        //判断当前目录是否存在
        if(!dir.exists()){
            //目录不存在，需要创建
            dir.mkdir();
        }

        try {
            file.transferTo(new File(basePath + filename));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return CommonResponse.createForSuccess(filename);
    }


    /**
     * 文件下载，用于上传的回显
     * @param fileName
     * @param response
     */
    @GetMapping("download")
    public void download(@RequestParam String fileName, HttpServletResponse response){
        try {
            //输入流，通过输入流读取文件内容
            FileInputStream fileInputStream = new FileInputStream(new File(basePath + fileName));

            //输出流，通过输出流将文件写回浏览器，在浏览器展示图片
            ServletOutputStream outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while((len = fileInputStream.read(bytes)) != -1){
                outputStream.write(bytes, 0, len);
                outputStream.flush();
            }

            //关闭资源
            outputStream.close();
            fileInputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
